Animal Style Fries (In-and-Out Copycat Recipe)

If you’ve ever been to In-N-Out, you know their Animal Style Fries aren’t just fries—they’re a lifestyle. Perfectly golden fries topped with gooey melted American cheese, sweet caramelized onions, and that tangy “secret sauce” (spoiler: it’s basically fancy thousand island). It’s messy, indulgent, and absolutely worth the napkins.

I don’t live near an In-N-Out, so making my own copycat version at home became non-negotiable. The good news? They’re ridiculously easy, and you’ll end up with the same crave-worthy, cheesy, saucy magic in under 30 minutes. And while you’re craving takeout, make sure to check out my super easy lemon pepper wings (vegetarian of course), my crunchwrap supreme dupe, and my chik-fil-a sandwich dupe!!

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What Are Animal Style Fries?

Animal Style Fries are one of the most famous “not-so-secret menu” items at In-N-Out Burger. They take plain fries to the next level with:

• Cheese slices melted right on top.
• Caramelized onions that are sweet, buttery, and golden.
• In-N-Out’s signature sauce, which is basically a mayo-ketchup-relish dream.

Together, you get that salty, sweet, tangy, savory combo that makes people line up in drive-thrus for hours.

Key Ingredients for Making Animal Style Fries

Here’s the rundown of what makes these fries taste like the real deal:

• French Fries: I go with store-bought frozen fries because they crisp up perfectly and save a ton of time. Choose thin-cut for the most authentic vibe, but my favorite are curly fries!
• American Cheese Slices: Don’t swap this out for cheddar or mozzarella—American cheese melts into that signature gooey layer. It’s what makes Animal Style Fries… well, animal style.
• Caramelized Onions: Slowly cooked with butter, water, sugar, and a pinch of salt until golden and jammy. These add sweetness and depth that balance the richness.
• “Secret Sauce”: My copycat version uses mayo, ketchup, relish, and (curveball) a splash of pickled jalapeño brine. The brine gives it a tiny kick and acidity that keeps the sauce from being too heavy.

Together, these ingredients are simple but build layers of flavor that make the dish taste just like In-N-Out’s original.

How to Make Animal Style Fries

1. Cook your fries until golden and crispy in the air fryer or oven.
2. Make caramelized onions by cooking them low and slow with butter, water, salt, and sugar until golden (the in-depth process is explained below).
3. Stir together mayo, ketchup, relish, and jalapeño brine for the sauce.
4. Lay hot fries on a plate, melt American cheese slices on top, spoon over onions, and drizzle generously with sauce.
5. Grab a fork (and some napkins) and dig in!

How to Caramelize Onions Quickly and Easily

1. Steam-sauté to soften: Add the onions and ½ cup water to a wide skillet over medium-high heat. Cook, stirring occasionally, 2–4 minutes until the onions look slightly translucent at the edges.
2. Enrich & start browning: Reduce heat to medium. Add the butter, sugar, and salt. Stir as the water cooks off and the onions turn glossy and pale gold.
3. Low-and-slow with mini deglazes: Drop heat to medium-low and keep cooking 8–12 minutes, stirring every 30–60 seconds. Add small splashes of water (1–2 tbsp at a time) as needed to deglaze the pan and prevent scorching—this speeds up even browning.
4. Finish jammy: When the onions are golden, soft, and a bit jammy (about 12–15 minutes total), pull from heat.

Quick tips: Use a wide skillet (more surface area = faster browning). If color is moving too fast, lower the heat and add a splash of water. For a subtle kick, replace the last splash of water with 1 tsp pickled jalapeño brine.

Common Mistakes to Avoid + Pro Tips

• Not crisping your fries enough: Soft fries will get soggy fast. Cook them until golden and crunchy for best results.
• Rushing the onions: Caramelized onions can’t be hurried—if you turn the heat too high, they’ll burn instead of sweeten. Low and slow is the way.
• Using the wrong cheese: American cheese is non-negotiable here—it melts like a dream.
• Over-saucing: Okay, maybe this isn’t a “mistake” (because who doesn’t love sauce), but drizzle, don’t dump. That way each fry gets coated instead of drowning.

Pro tip: Want to make it feel extra fast-food authentic? Serve your Animal Style Fries in a parchment-lined basket.

Serving Suggestions (Pairings)

These fries are the ultimate sidekick. Try pairing them with:

• Homemade In-N-Out style burgers (yes, I’ve got a dupe recipe for that).
• A frosty milkshake—chocolate, vanilla, or strawberry, just like the drive-thru.
• Veggie-loaded salads to balance the richness. (Trust me, it works!)

Or, just serve them as the main event at your next game day party. They’ll disappear fast.

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